Material breaking safety cartridge



Nov. 20', 1956v o. l.. CALLAHAN MATERIAL BREAKING SAFETY CARTRIDGE 1 NVEN TOR Filed Feb. 25,' 1951 .ww mw Q im Y H1 7 S. bv Sm s United States Patent() MATERIAL BREAKING SAFETY CARTRIDGE Oscar L. Callahan, West Frankfort, Ill., assiguor to Cardox Corporation, Chicago, Ill., a corporation of Illinois Application February 23, 1951, Serial No. 212,364 Claims. (Cl. 102-25) This invention relates to new and useful improvements in material breaking cartridges of the type employing a high pressure gas as the work performing medium.

The use of cartridges employing a highly compressed charge of air, or other gases, for breaking down materials, such as coal in mines, is well-known and has been widely practiced in recent years. The eiciency of this type of operation is dependent to a considerable degree on the speed and extent of opening of the Valve employed for eecting release of the charge of compressed gas from the cartridge.

The primary object of this invention is to provide a compressed gas cartridge having a quick-opening valve for completely releasing the material breaking charge in the shortest possible interval of time.

A further improtant object of the invention is to provide a compressed gas material breaking cartridge having a valve mechanism, located entirely in the discharge end of the cartridge, which may be actuated at the will of the operator to provide any desired work performing pressure.

Another important object of the invention is the provision of a material breaking cartridge which may be charged with gas compressed to any desired pressure, and which is provided with a valve mechanism that will operate automatically to quickly effect release of the complete material breaking charge as a result of stopping the delivery of the compressed gas to the cartridge.

A still further object of the invention is to provide a material breaking, compressed gas cartridge having a charge releasing valve mechanism which will operate automatically to eect discharge of the gas charge as a result of stoppage of the delivery of the compressed gas to the cartridge, and in which the valve mechanism may be adjusted to vary the time interval that will elapse between the stopping of the charging of the cartridge and the opening operation of the valve.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawing forming a part of. this specification and in which like reference characters are employed to designate like parts throughout the same,

Figure l is a longitudinal sectional view of one form of material breaking cartridge embodying the invention,

Figure 2 is a longitudinal sectional view of a modified form of material breaking cartridge, and

Figure 3 is a transverse sectional view taken on line 3-3 of Fig. 2.

In the drawing, wherein for the purpose of illustration are shown the preferred embodiments of the invention, and first particularly referring to Fig. l,` the reference character 4 designates a cartridge body having a com pressed gas charge receiving chamber 5. One end of the cartridge 4 is provided with an internally threaded laperture 6 for connection with a length of tubing, or the like, 7, through which a charge of compressed air, or other gas, is introduced into the chamber 5. The other end portion of the cartridge body 4 is internally shouldered 2,771,032 Patented Nov. 20, 1956 ice at 8 and is provided with threads 9 from the shoulder 8 'to the adjacent end of the cartridge body.

A11 annular seating ring 11 is positioned in abutting relation to the shoulder 8 and is held in place by the end of the discharge cap 12 which is connected to the cartridge body by the threads 9. The discharge cap 12 is of tubular construction to provide a discharge chamber 13 having diagonally arranged discharge ports 14 which are of suficient number and total cross-sectional area to effect rapid release of the gas from the cartridge chamber 5.

An annular guide member 15 is positioned in the bore of the discharge cap 12, at its outer end, and is held in place by the groove-seated retaining ring 16 and the housing 17 that is threadedly connected to the outer end portion of the discharge cap 12. A packing ring 18 seals the threaded connection between the housing 17 and the discharge cap 12. The housing 17 is formed with an internal cylinder 19 having a control chamber portion 19a, the purpose of which will be described at a later point.

The release of the material breaking chamber of cornpressed gas from the cartridge chamber 5 into the discharge cap 12 is effected by the automatic operation of the main annular valve 20 and the pilot valve 24, both of which are carried by the operating rod 21. The pilot valve 24 is integral with and is of sufficiently greater diameter than the rod 21 to form a shoulder or radial face at one end thereof which is grooved to receive the seating ring 25. Spaced axially along the operating rod 21 and immovably fastened thereto is a stop collar 23. Axially, movably positioned in the space between the radial face of the pilot valve 24 and the stop collar 23 is the main valve 2i). The inside diameter of the main valve is sufiiciently larger than the outside diameter of the rod 21 to accommodate a sealing ring 22 there-between. The rings 22 and 25, therefore, seal between the main valve 20 and the rod 21 and pilot valve 24, respectively.

When the opertaing rod 21 is moved axially outwardly relative to the discharge cap 12, or to the right in Fig. l, the main valve 20 will be clamped in sealing engagement with the seating ring 11 and the rings 22 anad 25, and will be spaced from the stop collar 23 to the extent illustrated. Any charge of the compressed gas delivered to the cartridge chamber 5, therefore, will be prevented from flowing into the discharge cap 12 by the combined sealing action of the seating ring 11, the main valve 20, the pilot valve 24, and the two rings 22 and 25.

The valve operating rod 21 slideably extends through the annular guide member 15 into the cylinder 19 of the housing 17. A pist-on 26, sealed by the ring 27, is threadedly connected to the end of the valve operating rod 21 and is positioned in the cylinder 19.

A passageway 28 extends axially through the entire length of the rod 21, the piston 26 and the pilot valve 24 to provide communication between the cartridge chamber 5 and the control chamber 19a of the cylinder. A portion of the passageway 28 formed in the pilot valve 24 is shaped to provide a seat 30 for the needle valve 29. The enlarged outer portion of the needle valve stem is adjustably threaded in the end portion of the passageway 28 and is formed with a longitudinal surface groove 29a which cooperates with the wall of the associated passageway to form a branch duct for by-passing gas, the flow of which is controlled by the needle valve when properly adjusted by means of the operating head 31. Lock nuts 32 are threaded on the needle valve stem to maintain the valve in the desired adjusted position.

A second branch duct 33 formed in the valve operating rod 21 extends from the passageway 2S to the outer surface of the rod adjacent the radial face of the pilot valve 24. This branch duct 33, therefore, is closed when the pilot valve seating ring 25 is in contact with the main valve 20, and is opened to provide direct communication 3 between the cartridge chamber 5 and the control chamber 19a through the passageway 28 when the said seating ring 25 is moved out of engagement with the main valve.

The valve operating rod 21 and piston 26 normally are urged in the direction to cause the pilot valve 24 `to engage. the4 main valve 20 with the seating ring 11 and the seating ring 25 'by a spring 34 which is positioned between the piston 26 and the annular guide member 15.

The operation of the cartridge illustrated in Fig. 1 will be described as follows:

When a material breaking operation is to be performed, the cartridge, in an uncharged condition but connected to a suitable source of supply of compressed air, or other gas, by means of the tubing 7, is placed in the previously prepared drill hole formed in the working face of the material, such as coal in a mine. At this time, the charge receiving chamber 5 of the cartridge body 4 is sealed from the discharge chamber 13 of the cap 12 by the illustrated engagement of the main valve with the seating ring 11 and the two rings 22 and 25. The charge receiving chamber 5, however, is in communication with the control chamber 19a of the cylinder 19. This communication is provided by the passageway 28 and the by-pass, groove 29a, formed in the surface of the needle valve 29.

T he compressed air is delivered to the charge receiving chamber 5 at a rate which will rapidly build up the pressure ltherein to the desired work performing pressure which, usually, will fall within a range of from 9,000 to 15,000 pounds per square inch. During'the rapid charging of. the chamber 5, compressed air is permitted to slowly How, or bypass, through the needle valve groove 29a, the space between the pointed end of the needle valve 29 and its seat 30, and the passageway 28, into the control chamber 19a. The compressed air pressure, therefore, will build up in the control chamber 19a at a considerably slower rate than in the charge receiving chamber 5.

When the chamber 5 has been charged to the desired working pressure, the delivery of compressed air to this chamber is stopped. The compressed air charge inthe chamber 5 acts at this timev upon the eiective crosssectional areas of the pilot valve 24 and the main annular valve 20 to maintain the seal between the chamber 5 and the discharge chamber 13. After a suicient amount of compressed gas has by-passed theneedle valve 29fand has flowed into the control chamber 19a, the piston; 26 moves a slight distance to the left, as viewed in Fig. l, This slight piston movement causes the pilot valve'ZA-to movea corresponding distanceto theleft toelectunseating of the pilot valve seating ring from the; main-.valve 20. This main valve, however, still remainsseatedagainst the rings 11 and22Y to prevent flow of the compressed air from the charge receiving chamber 5 into the discharge-chamber 13. However, the slight movement ofl the pilot valve 24 to the left unseals the branch duct 33 which permits compressed air` from the charge receiving chamber 5 to flow into the control chamber 19a. The ow of compressed air fromV the chamber Sinto the control chamber 19a then occurs at a much more rapid rate and very quickly builds upvthe pressure in the control chamber until it reaches a value which will cause the piston 26 to quickly move to the left until'the spring 34 is completely compressed and, thereby, functions as a stop for the piston.

Itwill be appreciated that the effective cross-sectional area of the piston 26 is suiciently greater than the effective cross-sectional areas of the pilot valve 24 andthe main annular valve 20 to cause the pistonfto bemoved to the left against the pressure of the spring 34 and the pressure of the compressed air charge in the chamber 5 when the pressure in the control chamber 19a reaches a certain value.

When the piston 26 is moved as far as it can go to the left, the stop vcollar 23, carried by the operating rod from its seating ring 11 and the charge of compressed air delivered to the chamber 5 then is very rapidly released to the discharge chamber 13 from which it flows through the ports 14 into the drill hole to effect the desired material breaking operation.

It will be appreciated, that the time interval which elapses between the stoppage of the delivery of compressed air to the charge receivingV chamberS and the unseating movement of the pilot valve 24, to open the second branch duct`33, is determined entirely by the setting of the needle valve 29 with reference to its seat 30. It willbe appreciated, therefore, that thisv time interval can be regulated, or varied, by changing the setting of the needle valve.

After the charge of compressed gas has been released from the cartridge chamber 5, the compressed gas that was delivered to the control chamberV 19a willbe exhausted into the chamber 5 through the passageway 28 and -theduct 33 and needle valve groove 29a until the` pressure in the control chamber 19a has been reduced to a value which willbe overcome by the force of the compressed spring 34. This. spring then moves the piston 26 to the right until the main valve 20 seats a-gainst the ring 11 and the'seating ring 25 of the pilot valve 24' engages the main valve 20. The cartridge then is in readiness to receive lanother charge of compressed air in its chamber 5 for performing a further material'breaki ing operation;

Referring now to Figs. 2 and 3 for a description of the modified material breaking cartridge illustrated therein,4 the cartridge body 35 isprovided with a compressed gas charge receiving chamber 36. One end of the cartridge 35'is provided with an internally threaded. aperture 37 for. connectionvwith'V a length of tubing, or. the like, 38, through: which a charge of compressed air, or other gas, is introducedkinto the chamber 36. The other end portion of the cartridge body 35 is reduced in diameter at 39 and is .provided with threads 40.

v A dischargey cap 41 is-connected to the cartridge body` 35-by4 the threads-40. The discharge cap 41 is of tubular construction to provide a discharge` chamber 42 having diagonally arranged discharge ports 43 which are of sutflcient number and total cross-sectional area to effect rapidrelease of gas from the cartridge chamber 36'. The inside diameter of the cartridge chamber 3.6 is less than that ofl the discharge chamber 42 so that the end of the/cartridge bodyy 35 forms an exposed annular valve seat 44 between the chambers 36 and 42. Thevbore of the outer end portion of the discharge cap 41 is of re* duced diameter to lprovide a valve rod guide 45.

`A -tubular adaptor member 46` is threadedlyv connected to the guide portion,45 .of the discharge,y capand-extends axially outwardly therefromA to'form lthe outer. wall of azcontrol chamber-'47. The outer end portiony of the adaptor'46is externally threaded at 48V and has. its end surface grooved to` receive va pilot valve seating ring y49.

A housing51` isconnected to the adaptor 46 by the threads .i4-8 to form a chamberV 52 adjacent the control chamberV 47. The threaded connections between the housing 51 .and the adaptor 46 and between theadaptor 46 andl the guidek portion- 45 of the discharge cap are sealed to prevent theescapeof gas bythe rings 53 and 54; respectively.

The release of the material breaking charge of compressed` gas yfrom the cartridge chamber 36 into the discharge. chamber `42y isy effected by automatic operation of themainuvalvey 55 andv the'pilotk valve'56, both of which aref.carried by thevalve operating rod 57. The main valvefSSis positionedain the dischargexchamber 42 andl is threadedly connected to" one endv of thepvalve themain valve 55 and the valve seat 44. A ring 59 seals' betweenthe adjacent surfaces of the operating rod 57 and the guide portion 45.

The operating rod 57 extends beyond the guide portion 45 of the discharge cap through the control chamber 47 and into the chamber 52 of the housing 51. The end portion of the rod 57 positioned within the chamber 52 is enlarged to form-a piston 60 having a radially enlarged portion 61 that is grooved to receive the sealing ring 62.

The pilot valve 56 is axially, slideably mounted on the operating rod 57 and the offset portion 61 of the piston to provide a low pressure chamber 63 between the pilot valve and the operating rod and piston. The portion of the bore of the pilot valve 56 that slideably engages the operating rod 57 is grooved to receive the sealing ring 64 while its larger diametered bore portion slideably engages the sealing ring 62 of the pist-on 6i).

The valve operating rod 57 has immovably fastened thereto a stop collar 67 for limiting axial movement of the pilot valve 56 away from the piston 60. The end of the pilot valve 56 adjacent the control chamber 47 is provided with a seating surface 66 for engaging the seating ring 49 to prevent the ow of gases from the chamber 52 to the control chamber 47 when the pilot valve is in its closed position.

A passageway 68 extends axially through the entire length of the operating rod 57, the piston 60 and the lock stud 58 to provide open communication between the cartridge chamber 36 and the chamber 52. An extension 68a of the passageway 68 is formed in the piston 60 and the operating rod 69 to connect the control chamber 47 and the chamber 52. It will be appreciated, therefore, that the chember 52 functionally cooperates with the passageway 68 and its extension 63a to provide a composite passageway between the cartridge chamber 36 and the control chamber 47. The passageway eX- .tension 68a is shaped to provide a seat 70 for the needle valve 71. The enlarged outer portion of the needle valve stem is adjustably threaded into the end portion of the passageway extension 68a and is formed with a longitudinal surface groove 72 which cooperates with the wall of the passageway extension 'to form a branch duct for by-passing gas, the flow of which is controlled by the needle valve when properly adjusted by means of the operating head 73. Lock nuts 74 are threaded on the needle valve stem to maintain this valve in the desired adjusted position.

A second branch duct 75 is formed between the outer surface of the pilot valve 56 and the housing 51. This branch duct 75, therefore, is closed when the pilot valve seating surface 66 is in contact with the seating ring 49 and is open to provide direct communication between the cartridge chamber 36 and the control chamber 47 when the said seating surface 66 and seating ring 49 are out of engagement.

The low pressure chamber 63 is in open communication with the discharge chamber 42 through the venting duct 76 formed in the operating rod 57 and, therefore, normally is at atmospheric pressure.

Thevalve operating rod 57 and piston 60 are normally urged in a direction to cause the main valve 55 to engage the valve seat 44 by a spring 77 which is positioned between the end of the housing 51 and a spring seat 78 abutting the oiset portion 61 on the piston.

The operation of the cartridge illustrated in Figs. 2 and 3 will be described as follows.

When a material breaking operation is to be performed, the cartridge, in an uncharged condition but connected to a suitable source of supply of compressed air, or other gas, by means of `the tubing 38, is placed in the previously prepared drill hole formed in the working face of the material, such as coal in a mine. At this time, .the charge receiving chamber 36 of the cartridge body 35 is sealedfrom the discharge chamber 42 of the cap 41 by the illustrated engagement of the main valve 55 with the v'alve seat 44. The charge receiving chamber 36, however, is in communication with the control chamber 47 through the passageway 68 and its extension 68a and the by-pass groove 72, formed in the surface of the needle valve 71.

The compressed air is delivered to the charge receiving chamber 36 at a rate which will rapidly build up the pressure therein to the desired work performing pressure, which usually will fall within the range of from 9,000 to 15,000 pounds per square inch. During the rapid `charging of the chamber 36, compressed air is permitted to ow freely into the chamber 52 through the passageway 68. From the chamber 52 the compressed air is permitted to slowly ow, or by-pass, through the needle valve groove 72, the space between the pointed end of the needle valve 71 and its seat 70, and passageway 68er, into the control chamber 47. The compressed air pressure, therefore, will build up in the control chamber 47 at a considerably slower rate than it builds up in the charge receiving chamber 36 and the chamber 52 in the housing.

When the chamber 36 has beencharged to the desired work performing pressure, the delivery of compressed air to this chamber is stopped. The compressed air charge in the chambers 36 and 52 acts upon the eifective crosssectional areas of the main valve 5S and its lock stud 58 and the greater eiective cross-sectional areas of the piston 60 and its offset portion v61, respectively, to supplement the pressure of the spring 77 in maintaining the main valve 55 in sealing engagement with the valve seat 44. After a sucient amount of compressed gas has bypassed the needle valve 71 and has owed into the control chamber 47, the pilot valve 56 moves a slight distance to the right, as viewed in Fig. 2. This slight movement of the pilot valve effects unseating of the seating surface 66 from the seating ring 49. The main valve 55, however, still remains seated on the valve seat 44 to prevent the ow of compressed air from the charge receiving chamber 36 into the discharge chamber 42. vHowever, the slight movement of the pilot valve 56 to the right unseals the secondary branch duct 75 which permits compressed air from the charge receiving chamber 36 to ow through the passageway 63 and the chamber 52 into the control chamber 47. The ow of compressed air from the chamber 36 into the control chamber 47 then occurs at a much more rapid rate and very quickly builds up the pressure in the control chamber until it reaches a value which, when combined with the pressure on the main valve 55, will cause the pistonv 60 to quickly move to the right and compress the spring 77.

It will be appreciated that the effective cross-sectional areas of the pilot valve 56 and main valve 55 are suiciently greater than the effective cross-sectional area of the piston 60 and its offset portion 61 to cause the piston to be moved to the right against the pressure of the spring 77 and the pressure of the compressed air in the chamber 52 when the pressure in the control chamber 47 reaches a certain value. The low pressure chamber 63 is maintained at substantially atmospheric pressure to prevent any resistance to movement of the pilot valve 56 toward and away from the piston 60.

When the piston 60 is moved to the right, the operating rod 57 will carry the main valve 55 away from its valve seat 44- and the charge of compressed air delivered to the chamber 36 then is very rapidly released to the discharge chamber 42 from which it flows through the ports 43 into the drill hole to effect the desired material breaking operation.

It will be appreciated that the time interval which elapses between the stoppage of delivery of compressed air to the charge receiving chamber 36 and the-unseating movement of the pilot valve 56, to open the second branch duct 75, is determined entirely by the setting of the needle valve 71 with reference to its seat 70. It will be appreciated, therefore, that this-time interval can be regulated, or varied, by vchangingthe setting of the needle valve71.

After. thel charge of compressed gas has been released from they cartridge chamber 36, the force of the compressed spring 77 will effect movement of the piston 60 and valve rod 57 to the left until the main valve 55 is seated against the valve seat 44. Further, the compressed spring 77, acting through the spring seat 78, will move the seating surface 66 of the pilot valve into-close proximity with the seating ring 49 so that the seating surface will immediately engage the seating ring upon the admission of another gaseous charge into the chamber 36.. The cartridge then is in readiness to receive another charge of compressed air in its chamber 36 for performing another material breaking operation.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to Without departing from the spirit of the invention or thescope ofthe subjoined claims. t

Having thus described the invention, I claim:

l. In combination, a material breaking cartridge having' a body formed of a chamberedsection, for receiving a compressed gas charge, and a discharge section conneeted end-to-end, means forming a valve seat between saidbody sections, said discharge section having lateral gas charge release ports and a control chamber, a main valve cooperating with said valve seat for controlling the release of the gas charge from the receiving section chamber to the release ports, means in the discharge section for forming a compressed gas ow path between the receiving section chamber and the control chamber, said flow path. being'forked to provide two separate branch ducts in onel portion thereof, valve means associated with one of said branch ducts and adjusted to only partially restrict the flow of gas therethrough, separate valve means associated with the other of said branch ducts for opening and closing the latter, saidl last mentioned valve means having a surface area exposed to the maximum gas pressure to which said cartridge has been charged to hold the last mentioned valve means in a fully closed position during charging of the cartridge vand being movable to open said other branch duct after the cartridge has been charged and the restricted ow of gas through said one branch duct has increased the pressure of the gas in said control chamber to one'predetermined value relative to said maximum pressure, and differential pressure operated means, subjecteditosaid maximum pressure and to the control charnberpressure, for'rmoving the main valve oif of its seat when the gas pressure built up in the control chamber reaches a second andy higher predetermined value relative to said maximum gas pressure.

2. In combination, amaterial breaking cartridge having a body formed of a chambered section, for receiving aY compressed gascharge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports and a control chamber, a main valvecooperating with said valve seat for controlling the release of the gas charge from the receiving section charnber to the release ports, a rod connected to said main valve for Voperating the same and mounted for axial movement in said discharge section, means forming a compressed gas ow path between the receiving section chamber and the control chamber, said ow path being forked to provide two separate branch ducts in one portion thereof, a valve carried bysaid operating rod in operative association with one of said branch ducts and adjusted for only-'partially restricting the ovv of gas therethrough to regulate the'rateof'ow of gasv from the receiving section chambery tol the control chamber, separate valve means associatedv with the other of said branch ducts for openingandclosingthe latter, said last mentioned valve meansthavinga surface area exposed/tothe maximum gas pressure to .which said cartridge hasbeen charged to hold the last mentioned valve means in a fullyA closed position4 during charging of the cartridge and beingzmovableto: open said other branch duct after the cartridge has been charged and the restricted flow of gas through said` one^ branch duct has increased the pressure of the gas in-said control chamber to one predetermined value relative toV said maximum pressure, and differential pressure operatedv means, subjected to said maximum pressure' and the` control chamber pressure, for moving the main valve ol of its seat when the gas pressure built up in the control chamber reaches a second and higher'predetermined value relative to said maximum gas pressure.

3. In combination, a material breaking cartridge having a body formed of'a chambered section, for receiving a compressed gas charge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports and a control chamber, a main valve cooperating with said valve seat for controlling the release of the gas charge from the receiving section chamber to the release ports, a rod connected to said main valve for operating the same and mounted for axial movement in said discharge section, means forming a compressed gas flow path between the receiving section chamber and the control chamber, said ow path being forked to provide two separate branch ducts in one portion thereof, valve means associated with one of said branch ducts and adjusted to only partially restrict the llow of gas therethrough, separate valve means associated with the otherof said branch ducts for opening and closing the latter, said last mentioned valve means having a surface area exposed to the maximum gas pressure to which said cartridge has been charged to hold the last mentioned valve means in a fully closed position during charging of the cartridge and being movable to open said other branch duct after the cartridge has been charged and the restricted ow of gas through said one. branch duct has increased the pressure of the gas in the said control chamber to one predetermined value relative to said maximum pressure, and a differential pressure operated piston connected to said operating rod and subjected to said maximum pressure and the control chamber pressure for moving the main valve from its seat by` an increase in the pressure of the gas in said control chamber to a second and higher predetermined value relative to said maximum pressure.

4. In combination, a material breaking cartridge having a body formed of a chambered section, for receiving a compressed gas charge, and a discharge sectionconneeted end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports anda control chamber, a main valve cooperating with said valve seat for controlling release of the gas charge from the receivingv section chamber to the release ports, meansin thedischarge section for forming a compressed gas ow path between the receiving section chamber and the control chamber, said ow path being forked to provide two separate branch ducts for directy communication with the receiving section chamber, valve means associated with one of said branch ducts and adjusted to only partially restrict the ow of gas therethrough, separate valve means associated with the other of said branchy ducts for opening and closing the latter, said last mentioned valve means having a surface area exposed to the prevailing gas pressure of said charge, to hold said last mentioned valve means in a fully closed position during charging of the cartridge and being movable to open said other branch lduct after the cartridge has been charged and the restricted flow of gas through said one branch duct has increased the pressure of gas in said control chamberto one predetermined value relative to said charge pressure,y and valve operating means connected to said mainl valve'v and havingl av surface-'arca subjected to the' pressure' of' the gas delivered to the control chamber, for moving the main valve ot its seat against said charge pressure when the gas pressure built up in the control chamber reaches a second and higher predetermined value relative to said charge pressure.

5. In combination, a material breaking cartridge having a body formed of a chambered section, for receiving a compressed gas charge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gascharge release ports and a control chamber, a main valve seated on said valve seat by the pressure of the gas charge to prevent the release of the gas charge during charging of the cartridge, a valve operating rod connected to said main valve for limited axial movement relative thereto, means forming a compressed gas flow path in open communication with said control chamber, said ow path being forked to provide two separate branch ducts for communication with the receiving section chamber, valve means associated with one of said branchducts and adjusted to only partially restrict the vflow of gas therethrough, separate valve means rigidly mounted on said operating rod and associated with the other of -said branch ducts for opening and closing the latter, said lastmentioned valve means having a surface area exposed to the prevailing gas pressure of said charge to hold said last mentioned valve means in a fully closed position during charging of the cartridge and being movable to open said second branch duct by said limited movement of said operating rod relative to said main valve, and a piston connected to said operating rod and having a surface area exposed to the pressure in said control chamber for moving said rod to open said other' branch duct and rapidly increase the control chamber pressure when the restricted ilow of gas through said one branch duct has increased the control chamber pressure to one predetermined value relative to said charge pressure and for further moving said rod to move the main valve oi of its seat when the pressure in said control chamber is rapidly increased to a second and higher predetermined value relative to said charge pressure.

6. In combination, a material breaking cartridge having a body formed of a chambered section, for receiving a compressed gas charge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports and a control chamber, a main valve seated on said valve seat by the pressure of the gas charge to prevent the release of the gas charge during charging of the cartridge, a valve operating rod connected to said main valve for limited axial movement relative thereto, means forming a compressed gas ow path in open communication with said control chamber, said ow path being forked to provide two separate branch ducts for communication with the receiving section chamber, a valve carried by said operating rod in operative association with one of said branch ducts and adjusted for only partially restricting the flow of gas therethrough to regulate the rate of ilow of gas from the receiving section chamber to the control chamber, a pilot valve rigidly mounted on said operating rod in operative association with the other of said branch ducts for opening and closing the latter, said pilot valve having a surface area exposed to the prevailing gas pressure of said charge to hold the pilot valve in a fully closed position during charging of the cartridge and being movable to open said other branch duct by said limited movement of said operating rod relative to said main valve, a piston connected to said operating rod and having a surface `area exposed to the pressure in said control chamber for moving said rod to open said other branch duct and rapidly increase the control chamber pressure when the cartridge has been charged and the restricted iiow of gas through said one branch duct has increased said control chamber pressure to one predetermined value relative to said charge pressure and for further' moving said rod to move the main valve oi its seat when the pressure in said control chamber is rapidly increased to a second and higher predetermined relative value, and means urging said piston in a direction to move said main valve into its seated position and to close said pilot valve when the pressure in said control chamber drops below a fixed predetermined value.

7. In combination, a material breaking cartridge having a body formed of a chambered section, for receiving a compressed gas charge, and a discharge section connected end-to-end, means forming Ia valve seat between said body sections, said discharge section having lateral gas charge release ports and Ia control chamber, a main valve cooperating with said valve seat for controlling the release of the gas charge, means in the discharge section for forming yan intermediate chamber between said receiving section chamber and said control chamber, said intermediate chamber being `at all times in open communication with said receiving section chamber to equalize the gas pressures therein and in communication with said control :chamber through two separate branch ducts, valve means adjusted to only partially restrict the ow of gas through one of said branch ducts, separate valve means subjected to the pressures of the gas in the intermediate and control chambers for opening and closing the other of said branch ducts, said last mentioned valve means being held closed by the difference in the forces exerted by the gas pressures lin said intermediate and control chambers during charging of the cartridge and being opened after the cartridge has been charged :and the restricted flow of gas through said one branch duct has increased the pressure of the gas in said control chamber to one predetermined value relative to the pressure then prevailing in the intermediate chamber, and differential pressure operated means, subjected to the pressure of the gas in the intermediate chamber and, by opening of said pilot valve, to the opposed pressure of the gas in said control chamber and to the valve opening force exerted on the main valve by the gas pressure in said charge receiving section for moving the main valve oi its seat when the gas pressure built up in the control chamber is rapidly increased, by the opening of said pilot valve, to :a second and higher predetermined'value relative to the gas pressure then prevailing in the intermediate chamber.

8. In combination, a material breaking cartridge having a body formed of a chambered section, for receiving a compressed g-as jcharge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports, an intermediate chamber and a control lchamber, a main valve seated on said valve seat against the pressure of the gas in said receiving section chamber to prevent the release of the gas charge during charging of the cartridge, a valve operating rod connected to said main valve Iand extending into said intermediate chamber, 'said rod having a passageway therethrough to provide open communication at all times between and to equalize the gas pressures in said receiving section and intermediate chambers, means providing two separate branch ducts for controlled [communication between said intermediate -an'd control chambers, valve means adjusted to only partially restrict the flow of gas through one of said branch ducts, separate valve means subjected to the pressures of the gas in said intermediate and control chambers for opening and closing the other of said branch ducts, said last mentioned Valve means being held closed by the difference in the forces exerted by the gas pressures in said intermediate and control chambers during charging of the cartridge and being opened to rapidly increase the control chamber pressure after the cartridge has been charged and the restricted ilow of gas through said one branch duct has increased the control Ichamber pressure to one predetermined value relative to the intermediate chamber pressure, and differential pressuregoperatedmeans, subjected to the pressure of the gas in1tfheiinterrnediate'chamber and, by opening'of said pilot valve, to the opposed control chamber pressure' and to the valve opening force exerted on the main valve by the gas 'pressure in said charge receiving section for moving the main valve off its seat when the control chamber pressure is rapidly increased, by the opening of s-aid pilot valve, to a `second and higher predetermined value relative to the prevailing pressure in the intermediate chamber.

9. In combination, :a material breaking cartridge having a body formed of 'a chambered'section, for receiving a. compressed gas charge, and a discharge section connected end-to-end, means forming a valve seat between said body sections, said discharge section having lateral gas charge release ports, an intermediate chamber and a control chamber, a main valve, Iseated on said valve seat against the pressure` of, the gas insaid receiving section chamber to prevent the release of the gas `charge during charging of the cartridge, la valve operating rod connected to said mainvalve and extendinginto saidintermediate' chamber, said rod having a longitudinal passageway. therethrough to provide open communication at all times between and to equalizethe gas pressuresin said receiving section and intermediate chambers, means providing two separate branch ducts for controlled communication between said intermediate and control cham'- bers, valve means adjusted to only partially restrict the ilow of gas through one of said branch ducts, a separate pilot valve subjected to the pressures of the gas in said intermediate and control chambers and mounted for limited movement on said rod to open and close the other of said branch ducts, said pilot valve being held closed by the difference in the forces exerted by the gas pressures in said intermediate and controlchambers during charging `of the cartridge and being opened to rapidly increase the control chamber pressure'after the 'cartridge has been charged andithe restricted flow of gas through said; one

branch du-ct has increased the control chamber pressureto one predetermined value. relative to the pressure then prevailingin the intermediate chamber, and valve. operatingV means mountedton said operating rod Vand subjected to the gas pressure in said intermediate chamber and to the opposed force exerted on the main valve'by the-gaspressure in said receiving section chamber to'm'aintain said main valve in its seated position during charging of the cartridge, said valve operating means beingsubjected to control chamber pressure, by movement of the pilot" valve into its open position, for releasing saidm'ain valveV for movement 01T of its seat when the control chamber pressure is rapidly increased to a second and higher predetermined value relative to the prevailing pressure in the intermediate chamber. f

l0. In combination, a material breaking cartridge having a body formed with a chamber for receiving a compressed gas charge and lateral gas charge release ports spaced lon# gitudinally of said body from said chamber, means forming a valve seat in said body at a location between the chamber and the release ports, a valve cooperating with r said valve seat for controlling the release of the` gas charge v tive tothe 'delivery of the complete compressed' gas charge to the receiving chamber of the cartridge body,

and valve means operating in response to the application of fluid pressure to said fluid pressure operated means in a direction to .unseat the valve, after the elapse of an appreciable time interval following the delivery of the complete compressed gas charge to the receiving chamber of the-cartridge body, for greatly acceleratingfthe rate of vapplication of fluid pressure to said uid pressure operated means in' a direction-to unseat the valve to quickly move the valve to its unseatedlposition.

References Cited in the tile of thispatent UNITED STATES PATENTS 2,083,735 Noble June 15, 1937 2,083,739 Osgood June 15, 1937 2,083,979 Armstrong June 15, 1937 2,122,706 Arm-strong July- 5, 1938 

